The objective of the proposed research is to investigate the determinants of change in fertility plans following the birth of the first child. We will examine how discrepancies between pre-birth parenting expectations and post-birth experiences motivate women to change their fertility plans. Approximately 440 women will be interviewed in the second trimester of their first pregnancy and again at 3 and 12 months after birth. At the pre- birth interviews we will assess their fertility plans as well as their expectations about how childrearing will affect various spheres of their lives. The post-birth interviews will again measure fertility plans and will assess women's experiences with how childrearing has actually affected their lives on each of the dimensions for which we collected expectations data. Descriptive analyses will focus on the relationship between parenting expectations and experiences, as well as between pre- and post-birth fertility plans. Hypothesis testing will employ multiple regression to model the determinants of women's post- birth fertility plans. Specifically, we will regress post-birth plans on pre-birth fertility plans, discrepancies between pre-birth parenting expectations and post-birth experiences, and a set of control variables. The proposed research will extend previous work on both fertility motivation and the transition to parenthood in several ways. First, most previous studies of the motives determining fertility plans have examined these variables at only one point in time, thus presenting a static view of fertility decision-making. The present study, with its longitudinal design, will permit the first direct test of the theoretically appealing sequential model of fertility decision-making. Second, this study supplements of life course literature with its focus on the timing and sequencing of the transition to parenthood. It adds a new emphasis on the specific nature of first time mothers' experiences during this transition, and on how discrepancies between these experiences and their pre-birth expectations affect subsequent fertility.